北京市2018—2020年疱疹性咽颊炎相关CV-A6分子流行病学特征分析

Molecular epidemiological characteristics of coxsackievirus A6 associated with herpangina in Beijing from 2018 to 2020

目的了解北京市2018—2020年疱疹性咽颊炎(herpangina,HA)相关柯萨奇病毒A组6型(coxsackievirus A6,CV-A6)分子流行病学特征。方法收集2018—2020年北京市16个区哨点监测医院中就诊的18岁以下HA病例的基本信息及临床症状,利用real-time RT-PCR方法检测肠道病毒(enterovirus,EV)和CV-A6核酸,采用描述性统计方法分析HA病例流行特征。扩增CV-A6 VP1区并测序,采用IQ-tree软件进行最大似然法进行系统进化树的重建,对序列进行遗传进化分析。结果2018—2020年共收集HA病例2937例,EV阳性1373例,总阳性率为46.75%,其中CV-A6阳性占总阳性病例的29.42%(404/1373)。在CV-A6阳性病例中,性别比为1.08:1,发病高峰为秋季,主要症状为疱疹(93.32%,377/404)、发热(86.39%,349/404),全部为轻症病例。本研究新定义了CV-A6的E基因型,所测89条CV-A6全长VP1核苷酸序列进行的遗传进化和核苷酸相似度分析发现,均属于D3基因亚型。结论CV-A6是2018—2020年北京地区疱疹性咽颊炎主要病原之一,主要流行株为D3亚型。应开展HA病例的常规监测,及时分析CV-A6的分子进化特征。

Objective To understand the molecular epidemiological characteristics of coxsackievirus A6(CV-A6)associated with herpangina(HA)in Beijing from 2018 to 2020.Methods The basic information and clinical symptoms of HA cases under 18 years old in the 16 sentinel hospitals in Beijing from 2018 to 2020 were collected.Enterovirus(EV)and CV-A6 nucleic acid were detected by real time RT-PCR,and the epidemiological characteristics of HA cases were analyzed by descriptive statistical methods.The CV-A6 VP1 region was amplified and sequenced.The maximum likelihood method was used to reconstruct the phylogenetic tree by IQtree software,and the sequence was used for phylogentic analysis.Results From 2018 to 2020,a total of 2937 HA cases were collected,including 1373 EV positive cases.The overall positive rate was 46.75%.The CV-A6 positive cases accounted for 29.42%(404/1373)of all positive cases.Among the CV-A6 positive cases,the sex ratio was 1.08:1.The peak of incidence was in autumn,and the main symptoms were herpes(93.32%,377/404)and fever(86.39%,349/404).All patients were mild cases.In this study,the genotype E of CV-A6 was newly defined.The phylogenetic analysis and nucleotide similarity analysis of 89 full-length VP1 nucleotide sequences of CV-A6 indicated that all cases belonged to D3 gene subtype.Conclusions CV-A6 was one of the main pathogens of HA in Beijing from 2018 to 2020 and the dominant strains belonged to subtype D3.Routine surveillance of HA cases should be carried out to timely analyze the molecular evolutionary characteristics of CV-A6.